Daily walking reduces visceral adipose tissue areas and improves insulin resistance in Japanese obese subjects

Abstract

Objective: It is known that the accumulation of abdominal fat is one of the risk factors for atherosclerosis. Although exercise is commonly prescribed to reduce body weight, the efficacy of low intensity exercise for the reduction of abdominal visceral adipose tissue remains to be investigated. Research design and methods: Thirty one obese Japanese males (body mass index (BMI) ≥25) ranging in age from 32 to 59, participated in a 1-year follow up study and they were instructed to have a modest increase in daily activity and record their daily walking. Before and after exercise prescription, body composition, blood pressure, physical fitness i.e. aerobic exercise level, muscle strength and flexibility were recorded. Insulin resistance was evaluated using a homeostasis model assessment, the HOMA index. Results: HOMA index, parameters of body composition, blood pressure, triglyceride and HDL cholesterol were significantly improved. The aerobic exercise level, leg strength, weight-bearing index (leg strength/body weight) and the steps taken per day were significantly increased. By stepwise multiple regression analysis, Δvisceral adipose tissue area was the major determinant for ΔHOMA index. (ΔHOMA index=−0.386+0.016 Δvisceral adipose tissue area, r 2=0.267, P<0.01). Exercise capacity and calorie intake were not significantly related to Δvisceral adipose tissue area, while Δsteps per day was significantly correlated with Δvisceral adipose tissue area (Δvisceral adipose tissue area=−21.363−0.004Δ steps per day, r 2=0.184, P=0.0326). Conclusions: Taken together, intra-abdominal visceral adipose tissue is critically involved in insulin resistance and daily walking rather than improvement of exercise capacity correlated with the reduction of visceral adipose tissue in obese Japanese males.